JP2009533236A - Handheld power tool with shut-off delay device - Google Patents

Abstract

  The present invention relates to at least one electric drive mechanism and at least one electric device that requires electric energy to function, the electric drive mechanism, a cutoff delay device for the electric device, the electric drive mechanism, and the electric device. The present invention relates to a handheld power tool having at least one rechargeable battery for supplying power to the battery. According to the present invention, the handheld power tool is a consumable discharge protection device (8) that sets the delay time (Δt) of the shutoff delay device (3) based on the detected charge level of the rechargeable battery (9). ). The present invention further relates to a method for driving the handheld power tool.

Description

  The present invention provides at least one electric drive mechanism and at least one electric device that requires electric energy for function, the electric drive mechanism, and / or a shut-off delay device for the electric device, the electric drive mechanism, and the The present invention relates to a handheld power tool provided with at least one rechargeable battery for powering an electrical device.

Prior art Such handheld power tools are known. Here, for example, when the handheld power tool is shut off by releasing the corresponding key switch (Tasterdruecker), the rechargeable battery is completely disconnected from all electrical loads of the handheld power tool. This is usually done without time delay in the electric drive mechanism of a handheld power tool. This is because a post-operation or extension operation of the tool driven by the electric drive mechanism is undesirable. However, the interruption delay is significant for other electrical devices. An electrical device here is, for example, an additional measuring device, an inspection device or a control electronic circuit itself. While electrical components with high current consumption are normally shut off without delay, electrical devices such as control electronics that consume little current are advantageously shut off after a delay. The control electronics will take some time to be fully ready for operation, so if the handheld power tool is switched on again after the control electronics are disconnected, there will be some delay between the user's switching request and activation. Wasteful time occurs. This is not user-friendly and may cause malfunction, particularly with a manually operated tool. This is because it takes longer than the user's prediction to start the electric drive mechanism. Generation of dead time can be avoided by performing a cutoff delay of the control electronic circuit at the time of reuse within such a delay time. However, even an electric device that requires little electric energy for operation causes battery discharge in battery-powered handheld power tools. When the battery reaches the consumable discharge area, the battery is damaged.

Problem underlying the present invention The problem underlying the present invention is to prevent a consumable discharge of a rechargeable battery from occurring even when the interruption of at least one electrical device is delayed.

Means for Solving the Problem This problem is solved by providing a consumable discharge protection device that sets the delay time of the interruption delay device based on the detected charge level of the rechargeable battery.

  According to such a consumable discharge protection device, the extraction time of electric energy by the rechargeable battery is limited by the charge level itself of the rechargeable battery. Therefore, further discharge from the rechargeable battery to the electrical device is performed only within a predetermined range based on the charge level of the rechargeable battery.

Advantageous Embodiments According to one embodiment of the invention, the shut-off delay device comprises a consumable discharge protection device. In this way, the number of necessary elements can be reduced.

  In particular, the consumable discharge protection device sets the delay time of the cutoff delay device to be short when the charge level is low. As the charge level becomes smaller, the energy that can be taken out from the battery is made smaller, and the risk of reaching a consumable discharge area that is obstructive to the battery is reduced.

  Further, the cutoff delay device does not perform cutoff delay when the charge level falls below a predetermined charging limit value. That is, when the charge level falls below a predetermined charge limit value, the electrical device is shut off without time delay. This measure prevents further discharge of the battery.

  Furthermore, the present invention provides at least one electrical drive mechanism, at least one electrical device that requires electrical energy for function, the electrical drive mechanism and / or a shut-off delay device for the electrical device, and the electrical The present invention relates to a method for driving a handheld power tool provided with a drive mechanism and at least one rechargeable battery for supplying power to the electric device. According to the present invention, the charge level of the rechargeable battery is detected by the consumable discharge protection device, the delay time of the cutoff delay device is set based on the detected charge level, and the electrical device is Delayed by the delay time and blocked. With such a driving method, the extraction time of electric energy by the rechargeable battery is limited by the charge level itself of the rechargeable battery.

  According to another advantageous embodiment of the invention, the consumable discharge protection device sets the delay time of the interruption delay device to be short when the charge level is low. The short delay time shortens the time for the electric device to extract the electric energy from the battery, thereby reducing the discharge amount of the battery.

  Further, the shut-off delay device shuts off the electric device without time delay when the charge level falls below a predetermined charge limit value. In this case, the consumable discharge protection device may set the delay time to 0 s, or the interruption delay device may perform interruption without delay.

  Particularly advantageously, only a set value is employed as the delay time. The value of the delay time can be, for example, an integral multiple of the set time.

  According to another advantageous embodiment of the invention, the consumable discharge protection device sets the delay time to continuously change until the charge level reaches the charge limit value. By continuously changing the set value of the delay time, the cutoff delay device can continuously adapt the cutoff delay to the charge level.

  Instead of this, the consumption discharge protection device may be set so that the delay time changes stepwise with the charge level.

  According to another advantageous embodiment of the invention, the charge level is determined by determining the battery voltage of the rechargeable battery by means of a consumable discharge protection device. Battery voltage varies with charge level during full or partial discharge of the battery. Based on the battery voltage, the charge level of the battery is uniquely inferred in the load region. When the battery is based on a lithium ion cell, the battery voltage decreases sharply as the charge level decreases. If this type of battery continues to discharge, a sudden drop in battery voltage must be monitored even if the current consumption by the electrical device is small.

  According to another advantageous embodiment of the invention, the battery voltage is measured with a corresponding current under a given electrical load. When the battery voltage is obtained continuously or at predetermined intervals during driving, the battery voltage is loaded by an electric load such as an electric drive mechanism. In order to make an inference of the charge level of the battery, the battery voltage must be measured along with the corresponding current. If the battery characteristic curve is known from this measurement, the no-load voltage or charge level of the battery can be inferred.

  Alternatively or in addition, the battery voltage can be measured in a substantially no current state. For example, if the battery voltage is measured after the electrical drive mechanism and all elements having high current consumption are shut off, a no-current measurement is performed for the no-load voltage of the battery.

  According to another advantageous embodiment of the invention, the consumable discharge protection device allows the electric drive mechanism to be switched on only when the charge level exceeds the electric drive mechanism switch-on threshold. For this purpose, the electric drive mechanism switch-on threshold is selected such that the charge level of the battery can guarantee the driving of the handheld power tool over a predetermined time corresponding to the application state.

  Furthermore, the consumable discharge protection device allows the electrical device to be switched on only when the charge level exceeds the electrical device switch-on threshold. This measure prevents further discharge of the battery due to re-switching on of the electrical device. Since the electric load of the electric device is smaller than the electric load of the electric drive mechanism, the electric device switch-on threshold is much smaller than the electric drive mechanism switch-on threshold.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be described in detail below with reference to the embodiments shown in the drawings.

  FIG. 1 shows a schematic diagram of a handheld power tool provided with a shut-off delay device. FIG. 2 shows a graph representing the relationship between the delay time and the battery voltage.

  FIG. 1 shows the basic structure of a handheld power tool 1 driven by a rechargeable battery. FIG. 1 shows only parts important for turning on and off the electric power tool 1. The operation unit 2 is connected to a cutoff delay device 3, and this cutoff delay device 3 acts on the electric drive mechanism 6 and the electric device 7 of the electric power tool 1 via the switching devices 4 and 5. The switching device 4 is assigned to the electric drive mechanism 6, and the switching device 5 is assigned to the electric device 7. Furthermore, the electric power tool 1 has a consumable discharge protection device 8 which is a part of the interruption delay device 3 in this embodiment. Parts of the electric power tool 1, particularly the electric drive mechanism 6 and the electric device 7 are supplied with power from a rechargeable battery 9. However, the corresponding feed lines are not shown. The electric device 7 is, for example, the control electronic circuit 10 of the electric power tool 1. The operation unit 2 is configured as a push button of the key switch 11, for example. The switching devices 4 and 5 can also be part of the shut-off delay device 3. Alternatively, one of the switching devices 4 and 5 may be directly connected to the operation unit 2. In the switching device 4 assigned to the electric drive mechanism 6, there are many cases where it should be ensured that the electric drive mechanism and thus the electric tool are stopped with as little delay as possible.

In the electric tool 1 provided with the interruption delay device 3, the following functions are performed. That is, when the user operates the operation unit 2 to shut off the electric tool 1, a cutoff time t ₀ at which the electric tool 1 is cut off from the operation unit 2 to the cutoff delay device 3 is set. The charge level of the rechargeable battery 9 is determined by a computing device not shown and a corresponding signal is supplied to the consumable discharge protection device 8. The wear / discharge protection device 8 sets a delay time Δt for the interruption delay of the electric device 7 based on the charge level of the rechargeable battery 9. Delay time with respect interruption of the electric drive mechanism 6 Delta] t is not set in this embodiment, blocking delay device 3 to cut off an electric drive mechanism 6 at the time t _0. The interruption here means that the electric load (electric drive mechanism 6 in this case) is completely disconnected from the rechargeable battery 9. When the electric device 7 is cut off, the cut-off delay device 3 cuts off the electric device 7 at the time point t ₀ + Δt in consideration of the delay time Δt set by the consumable discharge protection device 8. That is, after the operation unit 2 is operated, the electric drive mechanism 6 is cut off without delay, and the electric device 7 is cut off with a delay time Δt. In this embodiment, the charge level of the rechargeable battery 9 is detected by obtaining the battery voltage U. The battery voltage is also used as an input value of the consumable discharge protection device 8 at the same time.

In the graph of FIG. 2, the vertical axis indicates the delay time Δt, and the horizontal axis indicates the relative battery voltage U / U _max . A value of 100% for U _max corresponds to the maximum battery voltage of the fully charged battery 9. The battery voltage U is a measure of the charge level of the battery 9. The wear and discharge protection device 8 defines a plurality of relationships between the battery voltage U and the delay time Δt for various fields of application, and these are shown as a graph in FIG. In the graph, a plurality of qualitative relationships between the delay time Δt set by the consumable discharge protection device 8 and the battery voltage U are shown as characteristic curves 12 to 16. Each voltage threshold value U _s corresponds to the charging limit value when the delay time Δt drops to zero, and is shown, for example, in the region of about 15% to about 50% of the maximum value U _max . The voltage threshold value U _s is selected to be lower in the graph of FIG. 2, and the shape of the characteristic curve can be seen above the voltage threshold value U _s . Voltage threshold U _s used at present is higher than shown in the graph of FIG. The size of the intersection Δt _m between the characteristic curves 12 to 16 and the straight line of the maximum value U _max is the maximum delay time of the respective characteristic curves 12 to 16. For small values of the battery voltage than the voltage threshold U _s, characteristic curves 12 to 16 have a constant delay time Delta] t = 0. Battery voltage U is at below the voltage threshold U _s corresponding in all of the characteristic curve, the electric device 7 is interrupted without delay. Therefore, in the following, it is discussed only the region above the respective voltage threshold U _s of each characteristic curve 12 to 16.

The step-like characteristic curve 12 shows a jumping change in the delay time Δt as the battery voltage U changes, and each voltage region corresponds to a fixed delay time value. The characteristic curve 13 shows how the delay time Δt continuously changes over the entire relative battery voltage U / U _max . Characteristic curve 14, the maximum value _U at 100% to 65% of the area of the _max take a fixed delay time Delta] t corresponding to the maximum delay time Delta] t _m, the battery voltage U at 65% to 20% of the area of the maximum value _{U max} dropped to Delta] t = 0 linearly with the, this value becomes the point of the threshold U _s. The characteristic curve 15 is indicated by a broken line, and takes a constant delay time Δt in the region of 100% to 50%, and rapidly decreases to Δt = 0 at 50%. The characteristic curve 16 has a constant delay time Δt corresponding to the maximum delay time Δt _m in the region of 100% to 65%, and decreases linearly with the battery voltage U in the region of 65% to 40%. At 40%, it rapidly decreases to Δt = 0.

  In addition to setting the delay time Δt for the shut-off delay device, the consumable discharge protection device 8 may set a switch-on threshold for re-switching on individual components of the power tool 1, such as the electric drive mechanism 6 and the electric device 7. it can. Here, the aforementioned charging threshold, i.e. the charging limit value, the switch-on threshold value or the corresponding voltage threshold value does not necessarily have to be fixed, based on at least one limit condition, e.g. the temperature measured directly around the battery, It can be adjusted.

It is the schematic of a handheld type electric tool. It is a graph showing the relationship between delay time and battery voltage.

Claims (15)

At least one electrical drive mechanism, at least one electrical device that requires electrical energy for function, the electrical drive mechanism and / or a shut-off delay device for the electrical device, and for supplying power to the electrical drive mechanism and the electrical device In a handheld power tool provided with at least one rechargeable battery,
Further, there is provided a consumable discharge protection device (8) for setting a delay time (Δt) of the interruption delay device (3) based on the detected charge level of the rechargeable battery (9). Handheld power tool.   The handheld power tool according to claim 1, wherein the shut-off delay device (3) comprises the consumable discharge protection device (8).   The hand-held electric tool according to claim 1 or 2, wherein the consumable discharge protection device (8) sets a short delay time (Δt) of the shut-off delay device (3) when the charge level is low.   The handheld power tool according to any one of claims 1 to 3, wherein the interruption delay device (3) does not perform an interruption delay when the charge level falls below a predetermined charging limit value. At least one electrical drive mechanism, at least one electrical device that requires electrical energy to function, the electrical drive mechanism and / or a shut-off delay device for the electrical device, and the electrical drive mechanism and power supply to the electrical device In a method for driving a handheld power tool provided with at least one rechargeable battery for
The charge / discharge protection device detects the charge level of the rechargeable battery, sets the delay time based on the detected charge level,
A method for driving a hand-held power tool, wherein an electric device is delayed by the delay time by an interruption delay device.   The method according to claim 5, wherein when the charge level is low, the consumption discharge protection device sets a delay time of the cutoff delay device to be short.   The method according to claim 5 or 6, wherein when the charge level is lower than a predetermined charge limit value, the electric device is cut off without performing a cut-off delay by the cut-off delay device.   The method according to claim 5, wherein only a set value is used as the delay time.   The method according to any one of claims 5 to 8, wherein the consumable discharge protection device is set so as to continuously change with the charge level until the delay time reaches the charge limit value.   The method according to any one of claims 5 to 9, wherein the consumption discharge protection device sets the delay time to change stepwise with the charge level.   The method according to any one of claims 5 to 9, wherein the charge level is determined by determining a battery voltage of the rechargeable battery by the consumable discharge protection device.   The method of claim 11, wherein the battery voltage is measured with a corresponding current under a predetermined electrical load.   The method of claim 11, wherein the battery voltage is measured in a substantially no current state.   The method according to any one of claims 5 to 13, wherein the consumable discharge protection device permits the electric drive mechanism to be switched on only when the charge level exceeds an electric drive mechanism switch-on threshold value.   15. A method according to any one of claims 5 to 14, wherein the consumable discharge protection device permits the electrical device to be switched on only when the charge level exceeds an electrical device switch-on threshold.

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